The Los Angeles City Council gave final approval Tuesday to placing its own proposal on the May 21 ballot to regulate medical marijuana dispensaries, bringing the total number of ballot measures on the topic to three.

If approved by voters, the measure would increase a tax on the sale of medical marijuana and allow only a limited number of dispensaries to remain open. It would allow roughly 100 dispensaries that opened prior to the city’s imposition of a 2007 moratorium on the facilities.

A loophole caused the number of storefront pot shops to balloon shortly after the moratorium took effect.

“This is a step in the right direction,” said Councilman Bill Rosendahl, who has cancer and uses medical marijuana as a pain reliever.

The latest ballot measure — proposed by Councilman Paul Koretz — is billed as a compromise between two petition-driven initiatives that will also be on the ballot in May.

One would increase the tax on marijuana from $50 to $60 for every $1,000 in sales but does not limit the number of dispensaries. The other would allow only the original group of about 100 dispensaries operating prior to the city’s 2007 ban on new shops.

The backers of the second proposal — United Food and Commercial Workers Local 770, the Greater Los Angeles Collective Alliance, and Americans for Safe Access L.A. — announced earlier they were abandoning support of their initiative in favor of Koretz’s proposal, although it will still appear on the ballot.

City Attorney Carmen Trutanich, who is running for re-election in the March primary, threw his support behind the Koretz measure.

“I believe this is the most sensible regulation we can come up with in this era of turmoil,” he told the council. “… This gives our city the opportunity to regulate medical and give medical marijuana to those people who truly need it, some sensibility. Let the voters speak… let’s put it in the hands of the public.”

Councilman Jose Huizar, who said he has received multiple complaints from constituents about marijuana dispensaries, voted against the ballot measure.

“It will not protect neighborhoods from the proliferation of marijuana,” he said, adding “whether over the counter or on the street, a sale is a sale. It’s illegal under California state law.”

Council members Jan Perry, Mitch Englander, Joe Buscaino and Bernard Parks also dissented.

Tuesday’s vote coincided with the first day of a state Supreme Court hearing on a case stemming from Riverside over the ability of cities to ban medical marijuana dispensaries. Use of marijuana for medical purposes is allowed in California, but is still illegal under federal law.